According to a recent study (Clin Gastroenterol Hepatol 2014; 12: 821-27), “in a large mulit-institutional IBD cohort, a low plasma level of 25(OH)D was associated with an increased risk of cancer, especially colorectal cancer.” The study reviewed data from 2809 patients who vitamin D levels check (total cohort 11,028 persons with IBD); nearly a third had vitamin [25(OH)D] levels less than 20 ng/mL. The median followup was 11 years. During this period, 7% developed cancer (excluding nonmelanoma skin cancer). Vitamin D deficiency was associated with an adjusted odds ratio of 1.82 of increased cancer risk.
Like so many other studies, this study is another reason for vitamin D manufacturers to feel pretty good. The associated editorial provides some helpful context (pgs 828-30). The evidence regarding vitamin D dates back to at least 1980 when there was an observed higher incidence of colorectal cancer (CRC) mortality in regions with low solar radiation levels. Similar findings were noted with breast cancer.
There is biologic plausibility to the importance of vitamin D with regard to cancer as it is involved in “cell signaling, cell proliferation, cell apoptosis, cell adhesion, angiogenesis and it can up-regulate tumor suppressor genes.” A number of reviews have shown an inverse relationship to vitamin D levels and CRC risk.
The editorial points out a number of potential flaws. “For instance, those who had vitamin D measured may have been among the more ill patients…they may have been the most malnourished.” “Whether patients had concurrent …primary sclerosing cholangitis was also omitted.”
Take-home message (from editorial): “Although the authors have identified an association, for several reasons it may be spurious…the jury is still out as to what impact maintaining normal vitamin D levels may have on reducing inflammation and modulating cancer risk in chronic inflammatory diseases. However, it is healthful to have adequate vitamin D.” In Manitoba, the authors recommend that all of their patients receive vitamin D supplementation. In areas with more sun, checking levels may be worthwhile.
- Explaining the Vitamin D Paradox | gutsandgrowth
- Common to be “D–ficient” | gutsandgrowth
- Vitamin D deficiency and metabolism in pediatric … – gutsandgrowth
- Vitamin D, IBD, and Causality | gutsandgrowth
- Will Vitamin D Prevent Osteoporosis –Probably Not | gutsandgrowth
Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist. This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.